Container construction and method therefor

ABSTRACT

A collapsible container formed of three individual blanks having at each corner an outside hingedly connected securing flange adhesively bonded to the outside surface of an adjacent side wall, and an inside securing flange adhesively bonded to the inside surface of an adjacent side wall. The securing flanges provide stacking strength. The hinge connections of the inside securing flanges are provided in blanks for the container with spaced apart openings to relieve stress when the container is collapsed from set-up position.

United States Patent [191 Stollberg et a1.

CONTAINER CONSTRUCTION AND METHOD THEREFOR Inventors: Ray H. Stollberg, Concord; Joseph W. Leakey, Danville, both of Calif.

Assignee: Crown Zellerbach Corporation, San

Francisco, Calif.

Filed: Oct. 13, 1972 Appl. No.: 297,413

US. Cl. 229/41 R, 229/23 R, 229/48 R, 229/49, 229/DIG. 2, 229/41 B Int. Cl B65d 5/36 Field of Search 229/23 R, 41 R, 49, 48, 229/D1G. 2, 41 B References Cited UNITED STATES PATENTS 9/1883 Buckingham 229/41 R 5/1903 McCord 9/1927 Hoye 229/45 1 1 Nov. 26, 1974 1,697,709 l/1929 Bliss 229/23 R 2,234,167 3/1941 Hothersall 229/23 R 2,274,765 3/1942 Zalkind 229/48 R Primary Examiner-William 1. Price Assistant Examiner-Douglas B. Farrow Attorney, Agent, or Firm-Stanley Bialos; Corwin R. Horton; Thomas R. Lampe [5 7] ABSTRACT 12 Claims, 13 Drawing Figures CONTAINER CONSTRUCTION AND METHOD THEREFOR BACKGROUND OF THE INVENTION This invention relates to containers of the so-called Bliss type, having inside and outside flanges at each corner and which are collapsible; and more particularly, to such type of container in which openings are provided in the hinge line of the inside securing flanges to relieve stress when the container is collapsed from set-up condition.

Containers formed of three units or blanks of flexible material (Bliss type), which have at each corner an inside flange adhesively secured to the inside surface of an adjacent side wall, and an outside flange adhesively secured to the outside surface of an adjacent wall, are well-known. They provide stacking strength by virtue of the two flanges at each corner. However, a problem has heretofore existed in rendering these containers collapsible to substantially flat condition from thier setup position without joint separation at the corners because of strain which weakens the adhesive bond and thereby causes separation at the corners when the container is collapsed.

SUMMARY AND OBJECTS OF THE INVENTION The invention hereof overcomes this problem by the provision of weakened portions in the form of elongated spaced apart openings in the container blank containing the hinge connection line of each inside flange. As a consequence, when suitably scored so that when the container is collapsed from set-up position each of a pair of opposite side walls project outwardly from the bottom wall with the securing flanges at a corner extending in opposite directions in substantially the same plane, the openings in the hinge lines or connections of the inner flanges allow complete disconnection or separation ofthe inner flanges from the corner edges of the adjacent side walls to which they were hingedly connected. As a result, undue stress at the corner is prevented, which could otherwise cause separation of liners of corrugated paperboard or, joint failure. At the same time, stacking strength of the set-up container is not sacrificed because of the two upright securing flanges still present at each corner.

With the score lines arranged to permit collapsing of the bottom wall and a pair of opposite side walls inwardly so that they are positioned between the other pair of opposite side walls, the outside flange at each corner folds inwardly and thus overlies the inside flange creating a bulky four-ply corner. The openings in the inner flange hinge connection provide increased flexibility to relieve tension or stress which could otherwise cause joint failure. At the same time, stacking strength still remains. In the latter construction, the hinge connection line for the outer flange is a multiple score line, desirably at least a double score line, to cooperate in providing increased flexibility and relieving tension at the stress points.

Advantageously, the container blanks are each made of paperboard, and desirably of so-called single-wall corrugated paperboard containing a single corrugating medium and a sheet of liner paper adhesively bonded to each side of the corrugating medium.

From the preceeding. it is seen that the invention has as its objects, among others, the provision of a collapsible Bliss" style container made of flexible sheet material and of three parts or blanks in which the corners have inside and outside securing flanges providing stacking strength, which is of an improved construction to relieve stress at the corners when the container is collapsed from set-up condition, and which is of simple and economical construction. Other objects will become apparent from the following more detailed description and accompanying drawings, in which:

DESCRIPTION OF DRAWINGS FIG. 1 is an isometric view of a preferred embodiment of the invention wherein the container is in fully set-up position;

FIG. IA is a similar view illustrating the container in partially collapsed position;

FIG. 1B is a similar view illustrating the container in completely collapsed condition;

FIG. 2 is a horizontal section of the container;

FIG. 3 is a plan view of a first blank or unit of material from which the container is made;

FIG. 3A is a plan view ofa second blank of such material;

FIG. 3B is likewise a plan view of the third blank;

FIG. 4 is a perspective view of the corner construction with the closures omitted, looking in the direction of arrow 4 in FIG. 1;

FIG. 5 is a view similar to FIG. 4 illustrating the arrangement of the corner of FIG. 4 when the container is in collapsed position;

FIG. 6 is an isometric view similar to FIG. 1 of another embodiment of the invention; parts being shown broken away to illustrate the construction more clearly;

FIG. 6A is an isometric view of the container of FIG. 6 in partially collapsed condition; parts being broken away for purposes of illustration;

FIG. 7 is a plan view of the central blank in the embodiment of FIG. 6; and

FIG. 7A is a plan view of a second blank; a third blank being of the same construction as that of FIG. 7A.

DETAILED DESCRIPTION The container hereof is known in the trade as a Bliss" type, which is formed of three individual pieces or blanks that can be readily erected to set-up position, by the apparatus and method disclosed InAssignees US. Pat., No. 3,659,505, dated May 2, 1972. A first of such blanks, illustrated in FIG. 3, comprises a substantially center rectangular bottom wall panel 2, side wall forming panels 3 hingedly connected along score lines 4 at each of opposite edges of the bottom wall panel. Closure flaps 6 are hingedly connected to side wall forming panels 3. Hingedly connected to bottom wall panel 2 along score lines 7 at opposite edges of bottom wall panel 2 are bottom securing flanges 8. A securing flange 9 is hingedly connected by a score line 11 to each of the opposite edges of side wall panels 3. In the set-up container, these flanges 9 are upright outside securing flanges. V-shaped notches 10 are formed between the ends of adjacent flanges 8 and 9 which provide bottom abutment joints in the set-up carton.

A second blank (FIG. 3A) comprises substantially rectangular side wall panel 12, a corner securing flange 13 hingedly connected to each edge of side wall panel I2, and a closure flap l4 hingedly connected thereto.

The hinge connection line for each of corner flanges 13 with side wall panel 12 includes spaced apart elongated openings in the form of complete slits or cuts 16, which may be slots if desired, formed by suitable cuts extending completely through the material, and short scores 17 which form breakable connecting bridges, the purpose of which will be described in greater detail hereinafter.

To enalbe the container to be collapsed substantially flat, wall panel 12 is provided with a pair of triangularly arranged score lines 18, each leading from a lower corner of panel 12 with the apex of the triangle on a central score line 19. A central score line 21 in line with score line 19 extends across closure flap 14 to the apex of the triangle formed by diagonal score lines 18. When the blank of FIG. 3A is attached the the blank of FIG. 3 in the set-up container, score lines 18, 19 and 21 permit side wall panel 12 to collapse outwardly from bottom panel 2 of the blank of FIG. 3, as can be seen from FIGS. 1A and 1B.

The third blank, shown in FIG. 3B, is of the same construction as the blank of FIG. 3A, and, conse quently, the same reference numerals are applied.

With reference to FIGS. 1, 1A and 1B, which illustrate the set-up container, it will be noted that the blanks are secured together with flanges 8 on bottom wall panel 2 upright and adhesively bonded to side walls 12; and the corner securing flanges 9 of side walls 3 are secured upright by adhesive bonding to the outside surfaces of side walls 12 at the corners, while flanges 13 on side walls 12 are adhesively bonded to the inside surfaces at the corners of the container side walls 3.

Thus, at each corner there are two upright or upstanding securing flanges which not only act to secure the container parts or units together, but provide stacking strength when containers containing product are stacked one on top of the other. It is to be noted that the elongated openings 16 are relatively narrow, and are coincident with the hinge connection line along which they are formed so that the width of the flanges at the corners is substantially unaffected, and stacking strength provided by the pair of securing flanges at each corner is not impaired. Also, the aforementioned bridge connections are substantially the same width as the openings. One of these securing flanges at each corner is an inside flange and the other an outside flange. In collapsing the containers, opposite side walls 12 collapse outwardly, as is shown in FIG. 1A, and the container can be completely collapsed to substantially flat condition, as is shown in FIG. 18.

With reference to FIGS. 4 and 5, wherein FIG. 4 illustrates a corner construction of the set-up container, and FIG. 5 illustrates the position that adjacent walls assume in the collapsed condition, it will be noted that as wall 12 is collapsed outwardly, it assumes a position substantially in line with wall 3 of the first blank with the corner flanges 9 and 13 extending in opposite directions. As a result of such collapsing, an outward pull is extended on the inside flange 13 at each corner by wall 12; and if the flange remained connected at its hinge line, the adhesive bond between it and wall 3 would break with consequent joint failure.

However, the elongated openings 16 and the short bridge connections 17 which can break under the described pulling stress, result in complete separation of about 1/4 to 3/8 inch of the inner flange 13 from the side wall panel 12 at the hinge connection line, thus preventing undue stress at the corner which would otherwise cause either the inner or the outer flange to tear loose from the side wall to which it is adhesively bonded or cause buckling of the outer flange with resultant joint failure. At the same time stacking strength is not impaired because both flanges 9 and 13 at each corner remain bonded to the adjacent side wall surface. In this connection, cuts 16 are relatively long, and bridge connecting scores 17 are relatively short so that they can be readily broken under the aforementioned pulling stress. The container is initially manufactured in set-up condition, and then collapsed for shipment. The disconnection occurs the first time the container is collapsed. For a container of about 11 inches high, two cuts each of about 5% inches long with three breakable bridges 17 of about one-fourth inch in length are suitable, but these dimensions may vary.

The collapsible type container hereof is specially adapted for the packaging of solid products, such as commodities, including lettuce, and because of its collapsible character, it is a reusable container. It may be of any suitable size, and it is desirably made of so-called single-wall, corrugated paperboard comprising corrugating medium and two plain liner sheets adhesively bonded thereto. In the embodiment of the invention illustrated adapted for the packaging of lettuce, the stock material is heavy, B-flute, single-wall, corrugated paperboard about three-sixteenths inch in overall thickness and 275 lb. test. The container has an overall length of about 22 inches, an overall width of about 16 inches, and an overall height of about l 1 inches, with cuts and bridges of the dimensions indicated previously. Instead of cuts, the openings 16 may be slots. Although closure flaps are preferably employed, they may be omitted as the container can be closed with a conventional telescoping cover.

The embodiment of the invention illustrated in FIGS. 6 through 7A is of the same three piece Bliss" style described with reference to the first embodiment, except that the bottom wall panel, the securing flanges hinged thereto, and the pair of opposite side wall panels secured to such flanges are provided with a score line arrangement enabling the container to be collapsed inwardly with the bottom wall panel and the pair of side wall panels secured thereto between the other pair of side wall panels. The first blank for this construction, illustrated in FIG. 7, comprises bottom wall panel 31 hingedly connected along score lines 32 to a pair of opposite side wall panels 33 to which closure flaps 34 are hingedly connected. A bottom securing flange 36 is hingedly connected along score line 37 to each of 0pposite ends of bottom panel 31 transverse to score lines 32, and outside corner securing flanges 38 are hingedly connected along at least a double score line 39 to the respective edges of side wall panels 33.

A second blank is illustrated in FIG. 7A, and comprises side wall panel 41 having hingedly connected thereto along each of opposite edges an inside corner securing flange 42. Each hinge connection for a securing flange 42 includes spaced slots 43 formed by removal of material to enhance flexibility, and bridging scores 44, which do not break because of the manner in which the container collapses.

The third blank (not shown) is of the same construction as the blank of FIG. 7A, and the same reference numerals are applied thereto in the drawings of the setup container.

To provide for the inward collapsing, the bottom wall panel 31 is formed with a central score line 44 and triangularly arranged pairs of score lines 46 having their apices substantially on score line 44 but spaced apart; a ventilation slot 45 being between the apices of score lines 46. Central score line 44 extends across bottom securing flanges 36, which are notched at their ends at 47 to accommodate the lower ends of outside securing flanges 38; and side panel 41 and its connected cover have a central score line 47 in line with score line 44 in the set-up container.

In the set-up container, as can be seen from FIGS. 6 and 6A, the securing flanges 28 on one pair of opposite side walls 33 are outside flanges and the securing flanges 42 on the other pair of side walls 41 are inside flanges. Thus, at each corner there is an upright outside flange and an upright inside flange providing the aforementioned stacking strength. It will be noted from FlG. 6A that when the container side walls 41 are collapsed inwardly between side walls 33, each outside flange 38 folds inwardly along its hinge connection line creating a bulky corner of four ply thickness (the two securing flanges and the two walls attached thereto). This results in pressure being applied at the corner because of the bulk of material present, which frequently causes the outer securing flanges 38 to be torn away with consequent joint failure. The material removed as a result of the slots 43 relieves tension at the stress points, thus preventing possible joint separation. In this embodi-v ment the openings 43 should be relatively wide slots to eliminate bulk. To relieve stress further, the multiple score line 39 facilitates bending of securing flange 38 inwardly around the corner by providing increased flexibility at the hinge connection line. Although a double score line is suitable, more scores may be provided.

In the FIG. 6 embodiment, the dimensions, including the length of elongated openings 43, can be the same as described for the first embodiment although they are not critical. Usually about one-fourth inch of material removal in formation of the slots is suitable. It is only necessary to remove enough material to decrease the aforedescribed bulk sufficiently to relieve stress when the container is collapsed.

We claim:

I. A blank construction for a collapsible container of flexible sheet material having score lines arranged for folding of the container to collapsed condition when empty comprising three blanks securable together; a first of said blanks comprising a central substantially rectangular bottom wall panel, a substantially rectangular side wall panel hingedly connected to each of a pair of opposite edges of the bottom wall panel, a securing flange hingedly connected to each of the remaining edges of said bottom wall panel, and a securing flange hingedly connected to each edge of each side wall panel; a second and third of said blanks, each comprising a substantially rectangular side wall panel and a securing flange hingedly connected to each of opposite edges of each of the latter side wall panels; the securing flanges on said bottom wall panel being securable to the side wall panels of said second and third blanks and the remaining securing flanges of said blanks being at the upright corners of the container when set up with a pair of flanges at each corner, one

of such corner flanges being an inside flange for adhesive bonding to the inside surface of the adjacent side wall panel, and the other of said flanges at each corner being an outside flange for adhesive bonding to the outside surface of the adjacent side wall panel; each of the hinge connections of said inside securing flanges including spaced apart openings coincident with the hinge connection to relieve stress at the corner when stress is placed on the corner as the container is collapsed from set-up condition.

2. The construction of claim 1 in which the inside securing flanges are on the side wall panels of said second and third blanks and the outside securing flanges are on the side wall panels of the first blank.

3. The construction of claim 1 further comprising closure flaps hingedly connected to the side wall panels.

4. The construction of claim 2 wherein each of a pair of opposite side wall panels includes a central score line and triangularly arranged score lines for collapsing of said side wall panels outwardly from the bottom wall panel in the setup container, and the hinge connection of each inside securing flange includes connecting bridges which can break under said stress when the side wall panels are collapsed outwardly.

5. The construction of claim 2 wherein said bottom wall panel is provided with a central score line and with a pair of triangularly arranged score lines having their apices substantially on said central score line, and the side wall panels of said second and third blanks each have a central score line in line with said central score line of said bottom wall panel whereby the set-up container can be collapsed with the side wall panels of said second and third blanks and the bottom wall panel positioned inwardly between the side wall panels of said first blank, the openings in the hinge connection of each of the inside securing flanges comprise slots and the hinge connection of each of the outside securing flanges comprising at least a double score line.

6. A collapsible container of paperboard comprising a bottom wall and pairs of opposite side walls having score lines arranged for folding of the container to collapsed condition when empty with the bottom wall of the container and a pair of opposite walls positioned inwardly between another pair of opposite side walls, and comprising three units having upright corner flanges adhesively bonded to the pairs of opposite walls of the container with a pair of flanges at each corner extending substantially the height of the container to provide stacking strength, one of said flanges at each corner being an outside flange overlying and adhesively bonded to the outside surface of the adjacent side wall, and the other of said flanges being an inside flange underlying and adhesively bonded to the inside surface of the adjacent side wall; each inside flange being connected at each corner to a side wall by a hinge connection, which includes at least two spaced apart slots coincident with the hinge connection, a bridge connection at the top and at the bottom of said hinge connection and each outside flange at each corner being hingedly connected to a side wall by at least a double score line, to relieve stress at the corner when stress is placed on the corner as the container is collapsed from a set-up position.

7. The container of claim 6 wherein said bottom wall is provided with a central score line and with a pair of triangularly arranged score lines having their apices substantially on said central score line, and each of a pair of opposite side walls has a central score line in line with said central score of said bottom wall for said inward collapsing of said pair of side walls and said bottom wall between a second pair of opposite side walls of the container.

8. A collapsible container of paperboard comprising a bottom wall and pairs of opposite side walls having score lines for folding the container to collapsed condition when empty with a pair of opposite side walls collapsed outwardly from the bottom wall, and comprising three units having upright corner flanges extending substantially the height of the container with a pair of flanges at each corner of the container to provide stacking strength, one of said flanges at each corner being an outside flange overlying and adhesively bonded to the outside surface of the adjacent side wall, and the other of said flanges being an inside flange overlying and adhesively bonded to the inside surfaces of the adjacent side wall, the corner edge of each inside flange being completely disconnected from the corner edge of an adjacent side wall in the set-up container.

9. The container of claim 8 wherein each of the outwardly collapsible side walls has a central score line and a pair of triangularly arranged score lines having the apex substantially on said central score line.

10. A collapsible container of paperboard comprising a bottom wall and pairs of opposite side walls having score lines for folding the container to collapsed condition when empty with a pair of opposite side walls collapsed outwardly from the bottom wall, and comprising three units having hingedly connected upright corner flanges extending substantially the height of the container to provide stacking strength, one of the flanges at each corner being an outside flange overlying and adhesively bonded to the outside surface of the adjacent side wall, and the other of said flanges at such corner being an inside flange overlying and adhesively bonded to the inside surface of the adjacent side wall, one of the hinge connection lines at each corner including spaced apart openings coincident with said line to relieve stress at the corner when stress is placed on the corner as the container is collapsed from set up condition.

11. The container of claim 10 wherein said spaced apart openings comprise at least two relatively narrow slots unaffecting the width of the securing flange, a relatively short and narrow bridge connection between said slots of substantially the same width as the slots, and a bridge connection at the top and at the bottom of the hinge connection of substantially said width.

12. The container of claim 11 wherein all the corner securing flanges are secured to side walls of the container by adhesive bonding. 

1. A blank construction for a collapsible container of flexible sheet material having score lines arranged for folding of the container to collapsed condition when empty comprising three blanks securable together; a first of said blanks comprising a central substantially rectangular bottom wall panel, a substantially rectangular side wall panel hingedly connected to each of a pair of opposite edges of the bottom wall panel, a securing flange hingedly connected to each of the remaining edges of said bottom wall panel, and a securing flange hingedly connected to each edge of each side wall panel; a second and third of said blanks, each comprising a substantially rectangular side wall panel and a securing flange hingedly connected to each of opposite edges of each of the latter side wall panels; the securing flanges on said bottom wall panel being securable to the side wall panels of said second and third blanks and the remaining securing flanges of said blanks being at the upright corners of the container when set up with a pair of flanges at each corner, one of such corner flanges being an inside flange for adhesive bonding to the inside surface of the adjacent side wall panel, and the other of said flanges at each corner being an outside flange for adhesive bonding to the outside surface of the adjacent side wall panel; each of the hinge connections of said inside securing flanges including spaced apart openings coincident with the hinge connection to relieve stress at the corner when stress is placed on the corner as the container is collapsed from set-up condition.
 2. The construction of claim 1 in which the inside securing flanges are on the side wall panels of said second and third blanks and the outside securing flanges are on the side wall panels of the first blank.
 3. The construction of claim 1 further comprising closure flaps hingedly connected to the side wall panels.
 4. The construction of claim 2 wherein each of a pair of opposite side wall panels includes a central score line and triangularly arranged score lines for collapsing of said side wall panels outwardly from the bottom wall panel in the set-up container, and the hinge connection of each inside securing flange includes connecting bridges which can break under said stress when the side wall panels are collapsed outwardly.
 5. The construction of claim 2 wherein said bottom wall panel is provided with a central score line and with a pair of triangularly arranged score lines having their apices substantially on said central score line, and the side wall panels of said second and third blanks each have a central score line in line with said central score line of said bottom wall panel whereby the set-up container can be collapsed with the side wall panels of said second and third blanks and the bottom wall panel positioned inwardLy between the side wall panels of said first blank, the openings in the hinge connection of each of the inside securing flanges comprise slots and the hinge connection of each of the outside securing flanges comprises at least a double score line.
 6. A collapsible container of paperboard comprising a bottom wall and pairs of opposite side walls having score lines arranged for folding of the container to collapsed condition when empty with the bottom wall of the container and a pair of opposite walls positioned inwardly between another pair of opposite side walls, and comprising three units having upright corner flanges adhesively bonded to the pairs of opposite walls of the container with a pair of flanges at each corner extending substantially the height of the container to provide stacking strength, one of said flanges at each corner being an outside flange overlying and adhesively bonded to the outside surface of the adjacent side wall, and the other of said flanges being an inside flange underlying and adhesively bonded to the inside surface of the adjacent side wall; each inside flange being connected at each corner to a side wall by a hinge connection, which includes at least two spaced apart slots coincident with the hinge connection, a bridge connection at the top and at the bottom of said hinge connection and each outside flange at each corner being hingedly connected to a side wall by at least a double score line, to relieve stress at the corner when stress is placed on the corner as the container is collapsed from a set-up position.
 7. The container of claim 6 wherein said bottom wall is provided with a central score line and with a pair of triangularly arranged score lines having their apices substantially on said central score line, and each of a pair of opposite side walls has a central score line in line with said central score of said bottom wall for said inward collapsing of said pair of side walls and said bottom wall between a second pair of opposite side walls of the container.
 8. A collapsible container of paperboard comprising a bottom wall and pairs of opposite side walls having score lines for folding the container to collapsed condition when empty with a pair of opposite side walls collapsed outwardly from the bottom wall, and comprising three units having upright corner flanges extending substantially the height of the container with a pair of flanges at each corner of the container to provide stacking strength, one of said flanges at each corner being an outside flange overlying and adhesively bonded to the outside surface of the adjacent side wall, and the other of said flanges being an inside flange overlying and adhesively bonded to the inside surfaces of the adjacent side wall, the corner edge of each inside flange being completely disconnected from the corner edge of an adjacent side wall in the set-up container.
 9. The container of claim 8 wherein each of the outwardly collapsible side walls has a central score line and a pair of triangularly arranged score lines having the apex substantially on said central score line.
 10. A collapsible container of paperboard comprising a bottom wall and pairs of opposite side walls having score lines for folding the container to collapsed condition when empty with a pair of opposite side walls collapsed outwardly from the bottom wall, and comprising three units having hingedly connected upright corner flanges extending substantially the height of the container to provide stacking strength, one of the flanges at each corner being an outside flange overlying and adhesively bonded to the outside surface of the adjacent side wall, and the other of said flanges at such corner being an inside flange overlying and adhesively bonded to the inside surface of the adjacent side wall, one of the hinge connection lines at each corner including spaced apart openings coincident with said line to relieve stress at the corner when stress is placed on the corner as the container is collapsed from set up condItion.
 11. The container of claim 10 wherein said spaced apart openings comprise at least two relatively narrow slots unaffecting the width of the securing flange, a relatively short and narrow bridge connection between said slots of substantially the same width as the slots, and a bridge connection at the top and at the bottom of the hinge connection of substantially said width.
 12. The container of claim 11 wherein all the corner securing flanges are secured to side walls of the container by adhesive bonding. 